The general aim of this project continues to be the establishment of a collaborative research project which provides theBranch with a resource whose priorities could easily be manipulated to rapidly evaluate hypotheses about environmental causes of cancer by analysis of information from pre-paid plans in existence many years and covering large groups of patients having particular cancers and comparable unaffected individuals. The main value of this resource is to provide a framework where emergent hypotheses can be evaluated relatively quickly. To some extent, the specific objectives of the next four years will depend upon the nature of these hypotheses as they emerge.